Swollen lip, please i need help

[Nameaz]

Two days ago i brought 3 balloon mollies and 5 male guppys. That night one of the guppies died not even 8 hours after i got him. and now Nel my betta who shares the tank with them seems to have a swollen bottom lip with a thin white line running across it. All the fish, they share a 45L planted tank. the day i brought the fish i also brought 3 new plants for the the tank.All the fish seem fine but Nel, who is swimming sluggishly. He is still eating but has trouble now having putting the food in his mouth.

Could it be stress? or maybe the start of cotton mouth?
or am i just being paranoid...
i hope its just me
The tank is also heated at 28C

[PinkDiamond]

I haven't dealt a lot with diseases, but I've done a lot of research on them. Without more info or pictures, these are my ideas:

- Could the tank have been stocked too quickly? (ie: did you add all of the new fish at once, which would suddenly increase the bio-load for the tank (the amount of ammonia being produced by fish) and causing the ammonia to spike, which might have killed the one fish you mentioned?) I usually add fish much more gradually, especially to a tank that's not that large. I would add one or two fish per week.

- Could the betta have been injured by one of the new fish? Possibly in some kind of fight? I've never seen a betta with a swollen lip, but my first thought would be injury

As far as the whiteness on the lip goes, I'd watch it. If the fish did have an open wound on it's mouth for some reason, then I think the wound could be vulnerable to (bacterial) columnaris infections (cotton-mouth, as you said). If the whiteness does start to look like columnaris, he will need antibiotics and quickly.

For now I would test the ammonia/nitrite/nitrate and pH levels in your water to make sure that they're acceptable and keep monitoring the fish to see if it gets worse.

Hope this helps? Hope your fishes are betta soon!

[Nameaz]

I did a test and their was a spike in ammonia so i guess that was it. He passed away last night, he didn't make it, i feel bad now for adding those fish, something to remember next time i guess. RIP Nel

[dramaqueen]

I'm sorry about your fish!